Clarify why 2 versions tomcat-juli.jar libs are deployed

For example in 7.10, the Tomcat version is 7.0.64.

In $NUXEO_HOME/nxserver/lib the following file:
tomcat-juli-7.0.64.jar
comes from the Tomcat server archive available here:
https://archive.apache.org/dist/tomcat/tomcat-7/v7.0.64/bin/apache-tomcat-7.0.64.tar.gz

In $NUXEO_HOME/bin the following file:
tomcat-juli.jar
comes from the Tomcat extras available here:
https://archive.apache.org/dist/tomcat/tomcat-7/v7.0.64/bin/extras/

Is there any reason we don't use the same release for the same lib version?